Preface. 1: The Study of Ball Lightning. 1.1. Definitions. 1.2. Explaining Ball Lightning Reports. 1.3. History of the Scientific Study of Ball Lightning. 1.4. Reported Characteristics. 1.5. Developing Models for Ball Lightning. 2: Thunderstorms and Lightning. 2.1. Introduction. 2.2. Thunderstorm Electricity. 2.3. Lightning. 2.4. Unusual Forms of Lightning. 2.5. Atmospherics and Radio Noise. 2.6. Recent Developments. 3: Phenomena that May Be Mistaken for Ball Lightning. 3.1. Physical Phenomena. 3.2. Physical Effects that Cause Distortion. 3.3. Psychological Aspects of Reports. 3.4. Limitations of Reports based on Visual Observation Alone. 3.5. The Importance of Physical Evidence. 4: Assessment of Electrical, Thermal, and Mechanical Risks. 4.1. Electrical Effects. 4.2. Thermal Effects. 4.3. Mechanical Effects. 5: Assessment of Risk of Death or Injury by Ball Lightning. 5.1. Deaths of Humans Attributed to Ball Lightning. 5.2. Deaths of Animals Attributed to Ball Lightning. 5.3. Injuries Attributed to Ball Lightning. 5.4. Summary. 5.5. Discussion. 5.6. Conclusions. 6: Assessment of Risk to Buildings. 6.1. Case Histories. 6.2. Interpretation. 6.3. Postscript: A Field Study. 7: Assessment of Risk to Aircraft. 7.1. Ball Lightning External to Aircraft. 7.2. Ball Lightning See Inside Aircraft. 7.3. Discussion. 8: Assessment of Risk to Trees. 8.1. No Clear Evidence of Contact Between Ball Lightning and a Tree. 8.2. Reports of Contact Between Ball Lightning and a Tree. 8.3. Conventional Linear Lightning and Trees. 8.4. Does Ball Lightning Damage Trees? 9: Photographs and Videotapes. 9.1. General Considerations. 9.2. Causes of Misidentification. 9.3. Still Photographs. 9.4. Films and Videotapes. 9.5. Instrumented Observations. 9.6. Conclusions. 10: The Existence of Ball Lightning. 10.1. The Problem of Random, Transient Phenomena. 10.2. Ockham's Razor and Other Philosophical Questions. 10.3. Skeptical Views. 10.4. Reliability of Reports. 10.5. Scientists and Skepticism. 10.6. Conclusions. 11: Ball Lightning Theories and Experiments. 11.1. Present Status of Ball Lightning Theory. 11.2. Aims of Ball Lightning Theory. 11.3. Classification of Models. 11.4. Plasma Models. 11.5. How is Ball Lightning Formed? 11.6. Energy Content of Ball Lightning. 12: Models Based on an Internal Energy Source. 12.1. Heated Sphere of Air. 12.2. Plasmoid and Vortex Plasma Ring Models. 12.3. Other Plasma Models. 12.4. Other Vortex Structures. 12.5. Internal Energy Models Powered by Electromagnetic Radiation. 12.6. Chemical Processes. 12.7. Dust, Droplets, Dirty Plasmas, Aerosols, and Fractal Structures. 12.8. Nuclear Processes. 12.9. Charge Separation. 12.10. Ions. 13: Models Based on an External Energy Source. 13.1. Direct Current Discharge Models. 13.2. Microwave Resonance Models. 14: Conclusions and Recommendations. Appendix A: Ball lightning questionnaire. Appendix B: Glossary. Appendix C: Bibliography. Index.